Paris Gun

Also called the "Kaiser Wilhelm Geschütz" ("Kaiser Wilhelm Gun"), they were often confused with Big Bertha, the German howitzer used against Belgian forts in the Battle of Liège in 1914; indeed, the French called them by this name as well. They were also confused with the smaller "Langer Max" (Long Max) cannon, from which they were derived. Although the famous Krupp-family artillery makers produced all these guns, the resemblance ended there. The German objective was to build a psychological weapon to attack the morale of the Parisians, not to destroy the city itself.

• Origin — German Empire • Type — Super heavy field gun • Is Ranged — yes • Is Artillery — yes • Used By — German Empire • Wars — World War I • Designer — Dr. Fritz Rausenberger • Manufacturer — Krupp • Weight — 256 t • Part Length — 21 m • Length — 34 m • Caliber — 211 mm, later rebored to 238 mm • Velocity — 1640 m/s • Max Range — 130 km • Breech — horizontal sliding-block • Elevation — 55 degrees • Illustration — Scale model of a Paris Gun on its fixed mounting, Wehrtechnische Studiensammlung Koblenz

• Illustration — Diagram of a Paris gun shell published in 1921 • Illustration — The damage caused by a shell landing on the Père Lachaise Cemetery on the 25 March 1918 The Paris Gun shells weighed 106 kg. The shells initially used had a diameter of 216 mm and a length of 960 mm. The main body of the shell comprised thick steel containing 7 kg of TNT. The small amount of explosive—around 6.6% of the weight of the shell—meant that the effect of its shellburst was small for the shell's size. The thickness of the shell casing, to withstand the forces of firing, meant that shells would explode into a comparatively small number of large fragments, limiting their destructive effect. A crater produced by a shell falling in the Tuileries Garden was described by an eyewitness as being 10 to across and 4 ft deep. The shells were propelled at such a high velocity that each successive shot wore away a considerable amount of steel from the rifled bore. Each shell was sequentially numbered according to its increasing diameter, and had to be fired in numeric order, lest the projectile lodge in the bore and the gun explode. Also, when the shell was rammed into the gun, the chamber was precisely measured to determine the difference in its length: a few inches off would cause a great variance in the velocity, and with it, the range. Then, with the variance determined, the additional quantity of propellant was calculated, and its measure taken from a special car and added to the regular charge. After 65 rounds had been fired, each of progressively larger caliber to allow for wear, the barrel was sent back to Krupp and rebored with a new set of shells. The shell's explosive was contained in two compartments, separated by a wall. This strengthened the shell and supported the explosive charge under the acceleration of firing. One of the shell's two fuzes was mounted in the wall, with the other in the base of the shell. The fuzes proved very reliable as every single one of the 303 shells that landed in and around Paris successfully detonated. The shell's nose was fitted with a streamlined, lightweight, ballistic cap and the side had grooves that engaged with the rifling of the gun barrel, spinning the shell as it was fired so its flight was stable. Two copper driving bands provided a gas-tight seal against the gun barrel during firing.

• Illustration — Map of central districts of Paris, showing where shells fired by the Paris Gun landed, June-August 1918, and a line indicating the direction of the German guns. (Some shells landed outside this area.) Based on Miller (1921), p. 735 • Illustration — The damage to St-Gervais-et-St-Protais Church (1918) The Paris gun was used to shell Paris at a range of 120 km. The gun was fired from a wooded hill (Le mont de Joie) near Crépy, and the first shell landed at 7:18 a.m. on 23 March 1918 on the Quai de la Seine, the explosion being heard across the city. Shells continued to land at 15-minute intervals, with 21 counted on the first day. On the first day, fifteen people were killed and thirty-six wounded. The effect on morale in Paris was immediate: by 27 March, queues of thousands had started at the Gare d'Orsay and, at the Gare Montparnasse, ticket sales out of the capital were suspended due to demand. The initial assumption was these were bombs dropped from an airplane or Zeppelin flying too high to be seen or heard, or perhaps an "aerial torpedo". Within a few hours, sufficient casing fragments had been collected to show that the explosions were the result of shells, not bombs. By the end of the day, military authorities were aware the shells were being fired from behind German lines by a new long-range gun, although there was initial press speculation on the origin of the shells. This included the theory they were being fired by German agents close by Paris, or even within the city itself, so abandoned quarries close to the city were searched for a hidden gun. Another possibility was that German forces had penetrated the front line, but authorities realized that such heavy artillery could not be moved and emplaced so quickly. The press reported the German gun's range as about 100 km, which amazed American ordnance officers, and the shells as 240 mm, compared to the 17 in caliber of heavy German siege shells. The previous world distance record was German bombardment of Dunkirk from 22 mi, while the best American gun had a range of 19 mi. The record was subsequently exceeded by the German Batterie Pommern at Koekelare, whose modified 38 cm SK L/45 "Max" gun could bombard Dunkirk from about 45 km (28 mi) away, with its shells reaching heights of roughly 10 km (6.2 mi), making Batterie Pommern the largest coastal artillery battery in the world in 1917. Experts thought that the German weapon might be a product of the Škoda Works. Three emplacements for the gun were located within days by the French reconnaissance pilot Didier Daurat, the path of the shells which landed in Paris having revealed the direction from which they were being fired. The closest emplacement was engaged by a 34 cm railway gun while the other two sites were bombed by aircraft, although this failed to interrupt the German bombardment. Between 320 and 367 shells were fired, at a maximum rate of around 20 per day. The shells killed 250 people and wounded 620, and caused considerable damage to property. The deadliest incident was on 29 March 1918, when a shell hit the roof of the St-Gervais-et-St-Protais Church, collapsing the roof onto the congregation then hearing the Good Friday service. A total of 91 people were killed and 68 were wounded. There was no firing between 25 and 29 March, when the first barrel was being replaced; an unconfirmed intelligence report claimed that it had exploded. Barrels were probably changed again between 7–11 April and again between 21–24 April. The diameter of the later shells increased from 21 to, indicating that the used barrels had been re-bored. A further emplacement, later identified as specifically designed for the Paris Gun, was found by advancing US troops at the beginning of August, on the north side of the wooded hill at Coucy-le-Château-Auffrique, some 86 km from Paris. The gun was taken back to Germany in August 1918 as Allied advances threatened its security. No guns were ever captured by the Allies. It is believed that near the end of the war they were completely destroyed by the Germans. One spare mounting was captured by American troops in Bruyères-sur-Fère, near Château-Thierry, but the gun was never found; the construction plans seem to have been destroyed as well.

• Illustration — A K 12 railway gun elevated to the firing position Under the terms of the Treaty of Versailles, the Germans were required to turn over a complete Paris Gun to the Allies, but they never complied with this. In the 1930s, the German Army became interested in rockets for long-range artillery as a replacement for the Paris Gun which had been specifically banned under the Versailles Treaty. This work eventually led to the V-2 rocket that was used in World War II. Despite the ban, Krupp continued theoretical work on long-range guns. They started experimental work after the Nazi government began funding the project upon coming to power in 1933. This research led to the 21 cm K 12 (E), a refinement of the Paris Gun design concept. Although it was broadly similar in size and range to its predecessor, Krupp's engineers had significantly reduced the problem of barrel wear. They also improved mobility over the fixed Paris Gun by making the K 12 a railway gun. The first K 12 was delivered to the German Army in 1939 and a second in 1940. During World War II, they were deployed in the Nord-Pas-de-Calais region of France; they were used to shell Kent in Southern England between late 1940 and early 1941. One gun was captured by Allied forces in the Netherlands in 1945.

• Illustration — "Big Bertha" in the Charlie Chaplin film The Great Dictator. A parody of the Paris Gun appears in the Charlie Chaplin movie The Great Dictator. Firing at the Cathedral of Notre Dame, the "Tomanians" (the fictional country that represented Germany) succeed in blowing up a small outhouse. The destruction of the St-Gervais-et-St-Protais Church inspired Romain Rolland to write his novel Pierre et Luce.